The effect of HCl and H2O on the H2S removing capacities of Zn-Ti-based desulfurization sorbents promoted by cobalt and nickel oxide

The Sulfur removing capacities of various Zn-Ti-based sorbents were investigated in the presence of H2O and HCl at high-(sulfidation, 650degreesC; regeneration, 800degreesC) and medium-(sulfidation, 480degreesC; regeneration, 580degreesC) temperature conditions. The H2O effect of all sorbents was not observed at high-temperature conditions. At medium-temperature conditions, the reaction rate of ZT (Zn/Ti : 1.5) sorbent decreased with the level of H2O concentration, while modified (ZTC, ZTN) sorbents were not affected by the water vapor. HCl vapor resulted in the deactivation of ZT sorbent with a cycle number at high-temperature due to the production of ZnCl2 while the sulfur removing capacities of ZTC and ZTN sorbents were maintained during 4-5 cyclic tests. In the case of medium-temperature conditions, ZT sorbent was poisoned by HCl vapor while cobalt and nickel added to ZT sorbent played an important catalytic role to prevent from being poisoned by HCl due to providing heat, emitted when these additives quickly react with H2S even at medium-temperature conditions, to the sorbents.